Roll subject to deflection



July 23, 1963 L. HoRNBos-rEL. 3,098,284

ROLL SUBJECT TO DEFLECTION Filed Aug; 22, 1961 INVENToR. Lloyd /fornose/35 34'@ 2721 272 27C BY atsazsi Patented `luly 23, 1963 3,998,284 RLLSUBJECT T DEFLECTION Lloyd Hornbostel, Beloit, Wis., assigner to BeloitIron Works, Beloit, Wis., a corporation of Wisconsin Filed Aug. 22,1961, Ser. No. 133,150 3 Claims. (Cl. 29-113) This invention relates to-a structure for a roll whose axis is subject to deflection in responseto a load applied to such roll, and more particularly, to a structurefor a roll that is subjected to a load tending to effect centraldeflection of the roll axis.

Although the instant invention may be useful in a number of arts, it isparticularly useful in the paper making art and will be describedprimarily in connection therewith. In paper machines there are a numberof different types of rolls of substantial size which are subjeoted toloads tending to deflect such rolls centrally. For example, wire returnrolls in a Fourdrinier paper machine are subject to -a load tending -toeffect central deflection thereof by vintue lof the weight of the rollsthemselves and of the Fourdrinier wire carried by the rolls, the tensionon the Fourdrinier wire, and, in the case of a driven roll, the forcecomponent resulting from the resistance or reaction of the wire itselfto the driving force. These forces tend to deflect the roll downwardlyin the middle yand this results in an undesirable guidance of' thetraveling wire, which it has been found advantageous to avoid bycounteraoting the tendency for downward deflection of the return roll inone manner or another.

In addition, in the case of plastic forming wires and also in the caseof felts, a deflection away from the plane of the traveling Wire or feltis often undesirable. The crowning of a roll to compensate fordeflection is, likewise, often undesirable because it tends to causedifferences in peripheral speeds laterally across the roll and thusdifferences in `the speeds of various portions of the plastic wires orfelts.

The instant invention affords a simple and unique roll structure for aroll subject to a load tending to cause deflection of its axis, whetheror not this load is merely the weight of the roll or an additional loadapplied via a forming wire, etc. that is supported yand driven by theroll. In the instant roll structure the crowning of the roll may bevaried Without rebuilding the roll or refinishing the surface thereof.The crowning of the roll may be Varied from a positive to a negativecrown, depending upon the operating needs. The crowning of the roll iseffected by fluid pressure control means which are actuated outside ofthe roll itself by the use of conventional pressure control devices. Thefluid pressure maintained within the roll is the fluid pressure whichdetermines the outer peripheral dimensions of the roll (whether it be aposi-tive or negative crown) in a predetermined manner.

In the instant invention, a supporting generally cylindrical roll bodyis provided to carry the bulk of the load which tends to deflect theaxis of ythe roll. Under ordinary use, of course, the weight of thissupporting body plus any load applied to the roll will tend to causesome deflection of the centroidal axis. rl'he instant invention mayprovide for compensation of this tendency to deflect by imparting acrown or a slightly increased peripheral dimension lto the centralportion of the roll. Alternatively, the instant invention may provide nocrown or even a negative crown, i.e. a slightly decreased peripheraldimension to the central portion of the roll. The cylindrical body ofthe roll is wrapped -by an expansible hose, which preferably is providedwith a larger fluid pressure passageway in the central region of theroll, so that the variations in crown may be selected `by variations inpressure. When the hose is subjected to increased interior fluidpressure, the hose will expand to a greater extent in the centralportion of the roll than it does at the ends, thus causing a positivecrown. On the other hand, as the pressure in the hose is decreased, thecrown decreases; and finally when the pressure is reduced to asuflicient extent a slightly negative crown is obtained by virtue of thefact that the hose portion with the larger fluid passageway in thecentral region lof the roll is capable of collapsing under moderateloads to a greater extent than the hose portions at the ends of the roll(having smaller fluid passageways therein). The extent of such fluidpressure determines the extent of the crowning of the rol-l. It will beappreciated that such hose means may have a number of forms in order toaccomplish the ends herein described, and such hose may be designed soas to effect crowning or a greater peripheral dimension in regions ofthe roll other than the central portion. In this respect, it will be`appreciated that the axis of prac-v tically any roll is subject to somedeflection in response to a load, but the instant invention is notnecessarily limited to correction of the effect of such deflection ofthe axis, since it permits other variations in the overall peripheraldimensions of the roll and, therefore, the contour of yany operatingsurface thereof.

The instant invention has a number of advantages resulting from theIfact that the crown or variations in peripheral dimensions of the rollmay be controlled within certain limits by variations in actuating fluidpressure. Such fluid pressure would control the dimensions of the crownindependently of temperature changes and other variables known to vexistin the operation of rolls of this type in paper machines or othermachinery. Moreover, fluid pressure is very easily controlled and theover-all operation is accordingly simplified.

It is, therefore, an important object of the instant invention toprovide an improved roll structure.

It is another object of the instant invention to provide an improvedstructure for a roll Whose axis is subject to deflection in response toa load applied to the roll, by providing the roll structure withselectively inflatible means of variable response to fluid pressure, andfurther providing means for varying the fluid pressure.

Yet another object of the instant invention is to pro vide a roll whoseaxis is subject to deflection in response to a load applied to the roll,said roll comprising a supporting cylindrical body, solid elastomer hosemeans wrapped peripherally about the outer surface of said body andpresenting an outer peripheral surface for said roll, said hose meansdefining a central fluid pressure receiving bore surrounded by a solidelastomer body of predetermined cross-sectional area of lesser size atthe central portion of said body than at the ends thereof, and means forselectively introducing fluid under pressure into said hose means toeffect maintenance of a greater outer peripheral dimension for the rollat its center than at its ends and withdrawing fluid from said hosemeans to effect maintenance of a smaller outer peripheral dimension forthe roll at its center than at its ends.

Other and further objects, features and advantages of the presentinvention will become apparent to those skilled in the art from thefollowing `detailed disclosure thereof i and the kdrawings attachedhereto and made a part hereof.

On the drawings:

FIGURE 1 is an essentially diagrammatic elevational View showing a rollembodying the instant invention wherein a positive crown is maintained;t

yFIGURE 2 is a View corresponding to FIGURE 1, but showing a rollembodying the instant invention wherein a negative crown is maintainedduring operation;

FIGURE 3 is an elevational view of a roll assembly embodying theinvention, with the roll itself shown in section and 'parts showndiagrammatically;

FIGURE 4 is an enlarged fragmentary detail view of the encircled areaindicated at IV in FIGURE 3;

FIGURE 5 is a view comparable to that of FIGURE 4 of the encircled areadesignated V in FIGURE 3; and

FIGURE 6 is a view comparable to FIGURES 4 and 5, but showing anotherembodiment of the instant invention.

As shown on the drawings:

:In FIGURE 1, a roll embodying the instant invention indicated generallyby the reference numeral 11 is shown mounted on suitable bearings 12 and13 which are in turn firmly secured to a fixed mounting such as thefloor F. The roll 11 is provided with a left hand stub shaft or shaftelement 11a which is rotatably received by the left hand bearing 12 anda right hand stub shaft 11b which is rotatably received by the righthand bearing 13. As will be noted, the axis X-11 for the roll 11 isdeflected downwardly below a horizontal or center line C-11 at themiddle of the roll 11 and this is caused by the load applied to the roll11 by virtue of the weight thereof and any other forces which might beapplied downwardly thereto. The deflection X-11 is, of course,exaggerated for purposes of simplication.

In addition, the roll 11 has a slight positive crown indicated at R-11on the top of the roll 11, which is loaded to some extent by a plasticforming wire W-1 traveling over the roll 11. The plastic forming wireW-l could also be replaced by a felt. It will be noted that the downwarddeflection D11 at the bottom of the roll 11 is somewhat greater than thecrown R-11 at the top, because no load is applied to resist thisdownward deflection D-11. Particularly in the case of conventionalmetallic forming wires, it is desirable to avoid forces which tend tocompact the wire laterally and which may tend to cause the wire to foldupon itself and create imperfections therein. For this reason, theembodiment shown in FIGURE 1 may be particularly useful as a return rollfor a conventional metallic forming wire, tending to cause the wire(here shown at W-l) to spread out laterally rather than compactlaterally as it passes over the roll 11. In some instances, this type ofcontrol on the lateral spreading or the lateral compacting of plasticwires and felts is desirable; but in other instances it may be desirableto cause the plastic wire or felt to be subjected to neither compactingor spreading forces (as would be the case with the substantiallyhorizontal roll surface presented at the top of the roll in FIGURE 3);and in other cases it may be desirable to effect slight lateralcompacting of the plastic wire or felt, as is the case in the embodimentshown in FIGURE 2.

Referring now to FIGURE 2 specifically, it will be seen that there isshown a roll 14 having a left hand stub shaft 14a suitably mounted inbearing 15 and a right hand stub shaft 14b suitably mounted in a bearing16. Again, the roll 14 is subjected to the load of its own weight (aswell as any other load applied thereto) so that the axis thereof X-14 isdeflected downwardly slightly from the theoretical center line C-14. Inthe embodiment of FIGURE 2, however, a negative crown is applied to theroll 14 by control of the fluid pressure in the manner which will bedescribed hereinafter, and the plastic wire W-2 (or felt) passing overthe top of the roll 14 is subjected to a slight lateral compacting forcein substantially the plane of the plastic wire W-2 (i.e. generallytangent to the top of the roll 14).

Referring now to FIGURE 3, it will be seen that there is shownIgenerally a roll 21 embodying the instant invention which is mountedwith conventional allochiral heads and stub shafts 22, 23 rotatablycarried in bearings 24, 25. The roll 21 comprises a generallycylindrical supporting body or shell 26 of metal or similar structuralmaterial secured to the heads 22, 23. The outer surface 26a of the shell26 is Wrapped peripherally with expansible hose means, indicatedgenerally at 27. The hose means 27 may comprise a plurality of hoseelements connected to each other or `connected to a common source offluid under pressure (not shown); but in any event the hose means 2'7preferably defines an overcoat on the shell 26 of substantially uniformannular thickness when the hose is in unexpanded form. Preferably, also,the hose layer 27 is covered by a protective shell or overcoat 29 whichpresents an outer peripheral surface 29a for the roll 21. The outerlayer or cover 29 is preferably made of vulcanized rubber `or othersolid elastomer, which is adequate to protect the roll and wearsatisfactorily against the wire or whatever part of the machine it willengage, but which is also suflciently yieldable to respond to theexpansion of the hose means 27 (in the manner hereinafter described).

The roll 21 in its unloaded condition would, of course, have acentroidal axis C-21 along the theoretical center line indicated inFIGURE 2; but in the position shown in FIGURE 2 wherein the roll issupported at its extremities by the bearings 24, 25, the weight of theroll will cause a central deflection represented in exaggerated mannerby the dashed line B-21. In addition, any load (other than the weight ofthe roll itself) applied to the top of the roll (here representeddiagrammatically by arrows 30a, b, c) would add to the deflection of thecentroidal axis of the roll 21.

In the unexpanded form of the hose means 27, this would result in aslight downward deflection of the outer peripheral surface 29a of theroll 21 in the region of the central load arrow 30b. The presentinvention provides means for compensating for this type of deflection soas to obtain a substantially horizontal top peripheral surface 29a ofthe roll 21 or even a centrally crowned surface, depending upon thedesired operation. This is accomplished because of the particular formof the hose means 27, which will be described in detail, and by virtueof the application of fluid under pressure to the hose 27. The fluidunder pressure such as air under pressure may ybe fed from a suitablesource S through a pressure control valve V-21 (both representeddiagrammatically), through a conduit 31 generally axially aligned withthe hollow head and stub shaft 23 and then through a radially alignedconduit 32 passing through the structural shell 26 and feeding into thehose 27. In conventional manner, a stationary fixture 33 rotatablyreceives the conduit 31 and affords communication therebetween and thesource of fluid under pressure S.

Referring now to FIGURES 4 and 5, it will be seen that the solidelastomer (Le. rubber) hose means 27 comprises a plurality of adjacentwraps, with some near the end of the roll indicated at 27a, 27b and 27Cin FIGURE 4 and some near the middle of the roll indicated at 27d and27e in FIGURE 5. These helical wraps 27a through e have in theirunexpanded form substantially the same overall cross-sectional Aarea andshape. But the portions of the hose 27 near the ends of the roll 21,i.e. the wraps 27a, b, c have central fluid pressure receivingpassageways 34a, b of relatively small peripheral dimension (orcircumference in the cross-sectional view of FIGURE 4), whereas the hosewraps 27d, e near the center of the roll 21 have central fluid pressurereceiving passageways 34d, e of substantially greater peripheraldimension. Expressed in other terms, the cross-sectional area of thesolid elastomer body of the hose wrap 27a is substantially greater thanthe cross-sectional area of the solid elastomer body of the central hosewrap 27d. Moreover, since substantially the same fluid pressure ispresent in each of the passageways 34a, b, d, e during operation theexpanding force per unit area is the same in each of the passageways34a, b, d, e, but the total force is greater (because of the greaterarea to which the fluid pressure is exposed) in the case of the largerpassageways 34d and e. The net result is that the same fluid pressure inall of the passageways will result in a substantially greater expansionof the hose means 27 in the central portion of the roll 21, and thisresults in predetermined increase in the overall peripheral dimension ofthe roll 21 in the central portion thereof. The increase ispredetermined by the uid pressure lapplied in the passageways 34a, b, c,d, e, which in turn is controlled by the valve V-21. l

It will thus be apparent that under certain conditions of the load, apredetermined pressure will provide the desired peripheral dimension orcrown in the central portion of the roll 21 (or any other portion ofsuch roll, if the hose form is changed); whereas a different iluidpressure in the hose `27 will result in a different central peripheraldimension `for the roll 21, which may be found to be particularlydesirable for a different condition of load on the roll 21. It will alsobe apparent that, if thehose 27 is evacuated or iiuid pressure iswithdrawn therefrom, for example, by means of 4an evacuating pump V viathe valve V-Zla, then the hose elements 27d and 27e having the largerfluid passages therein will tend to collapse more readily than the hoseelements 27a, 27b having the smaller fluid passageways therein. Theevacuation of pressure in the hose 27 may thus be carried out dependingupon the nature of the load 30a, 30b, 30C so that such load may tend tocollapse the hose portion 27 in the central part of the roll and thusbring about the formation of a negative crown, as demonstrated in FIGURE2. The valve means V-21 and V-Zla vthus provide means for selectivelyvarying the iluid pressure in the hose 27 in order to selectively varythe relative peripheral dimensions for the roll at .its center and atits ends.

As previously indicated, the Wraps 27a, 27b, etc. of the hose 27 are soclosely placed together that they will present a relatively eve-n outersurface, but it is preferable to employ a covering layer 29. In theembodiment of FIGURE 6, it will be seen that the cross-sectional shapeof hose wraps 27a and 2f7b may be altered so as to present la smootherouter sur-face indicated generally at 351. In FIGURE 6 elementscorresponding to those shown in FIGURE 3 are indicated by the prime ofthe same reference numeral. The essential difference in FIGURE 6 residesin the rectangular or `substantially square overall cross-sectionalshape of the hose wraps 27a and 27b, so as to present a substantiallysmooth outer or operating surface 35 which may be used without anovercoat. In other respects, the hose means 2.7' Ifunctions in themanner already described.

In the preferred embodiment of the instant invention, the peripheraldimension of the smaller passageways 34a is substantially smaller thanthat 'of the `langer passage- Ways 34d, so as to obtain Ian appreciabledifference in expansion or contraction effect, which is not directlyproportional to such differences in peripheral dimensions of thepassageway. In gener-a1, the larger peripheral dimen- 6 sions (i.e. forthe passageway 34d) should be Within the range of about 1`1/2 to 5 timesthe peripheral dimensions of the smaller passageways (Le. the passageway34a).

An additional feature of the invention resides in the correction `offelt travel in situations when the felt seam tends .to lag behind in thecentral portion of the felt. In such situations the central portion ofthe instant roll may be inflated so that the resultant peripheral speedof the roll is increased in the center and the lagging central portionof the felt seam will tend to catch up to the edges of the felt seam.(Deation of the roll, of course, is used to cause a normally leadingcentral portion of la ffelt seam to fall back in line with the edges ofthe felt seam.)

It wil-l be understood that modifications 'and variations may beeffected without `departing from the spirit yand scope of the novelconcepts of the present invention.

I claim as any invention:

1. A roll whose axis is subject to deilection in response to -a loadapplied to the roll, said roll comprising a supporting generallycylindrical body, `an expansible hose of generally unifonmcross-sectional area wra-pped helically about the youter surface of saidbody to present an outer surface of substantially uniform peripheraldimension when the hose is in unexpanded form, cover means surroundingthe outer periphery of the hose and presenting an operating rollsurface, said hose having a central iluid pressure receiving passagewayof substantially greater peripheral dimension at the central region ofthe roll than at the roll ends, and means for selectively introducingfluid under pressure into said hose means to effect relatively greaterexpansion of said hose in the central region of said roll andwithdrawing fluid from said hose means to effect maintenance of arsmaller outer peripheral dimension of the roll at the central region ofthe roll.

2. A roll as claimed in claim 1 wherein the overall cross sectionalshape of the hose is substantially rectangular so Ias -to presen-t asmooth outer surface for engaging said cover means.

3. A roll as claimed in claim l wherein the overall cross 4sectionalshape of the 'hose is generally annular and the peripheral dimension 'ofthe passageway of .the hose in fthe central region of the roll -iswithin the range of 11/2 to 5 times the peripheral dimension of thesmaller fluid pressure receiving plassageways in the hose at the ends ofthe roll.

Muskett May 22, 1917 Hausman Feb. 7, 1961

1. A ROLL WHOSE AXIS IS SUBJECT TO DEFLECTION IN RESPONSE TO A LOADAPPLIED TO THE ROLL, SAID ROLL COMPRISING A SUPPORTING GENERALLYCYLINDRICAL BODY, AND EXPANSIBLE HOSE OF GENERALLY UNIFORMCORSS-SECTIONAL AREA WRAPPED HELICALLY ABOUT THE OUTER SURFACE OF SAIDBODY TO PRESENT AN OUTER SURFACE OF SUBSTANTIALLY UNIFORM PERIPHERALDIMENSION WHEN THE HOSE IS IN UNEXPANDED FORM, COVER MEANS SURROUNDINGTHE OUTER PERIPHERY OF THE HOSE AND PRESENTING AN OPERATING ROLLSURFACE, SAID HOSE HAVING A CENTRAL FLUID PRESSURE RECEIVING PASSAGEWAYOF SUBSTANTIALLY GREATER PERIPHERAL DIMENSION AT THE CENTRAL REGION OFTHE ROLL THAN AT THE ROLL ENDS, AND MEANS FOR SELECTIVELY INTRODUCINGFLUID UNDER PRESSURE INTO SAID HOSE MEANS TO EFFECT RELATIVELY GREATEREXPANSION OF SAID HOSE IN THE CENTRAL REGION OF SAID ROLL ANDWITHDRAWING FLUID FROM SAID HOSE MEANS TO EFFECT MAINTENANCE OF ASMALLER OUTER PERIPHERAL DIMENSION OF THE ROLL AT THE CENTRAL REGION OFTHE ROLL.